joelfinley

[joelfinley]

Warm Blooded Characteristics of Tuna

Tunas are large, fast-swimming fish capable of traversing thousands of miles in a single migration period. One of the unique attributes of tuna is that, unlike most other fish, they maintain a warm blood temperature in the ocean.

Bluefin, bigeye, yellowfin, and albacore share warm-blooded attributes with shark species such as white sharks. In total, 35 fish species fall into the warm-blooded, which makes up 0.1 percent of aquatic species.

Tuna has a specialized blood vessel structure, known as a countercurrent exchanger, that warms the eyes, brain, muscles, and other body parts. This attribute has several advantages, with warmer muscles typically being more potent.

Warmer muscles enable extra bursts of predatory speed, with the bluefin tuna accelerating to 30 mph on average in 10 seconds. Tuna have streamlined fins, torpedo-shaped bodies, and smooth skin that reduce drag and help them achieve incredible speeds. Albacore, for instance, can regularly exceed 50 mph." The muscles' extra heat provides a power boost that enhances their ability to avoid predators, hunt prey, and travel vast distances during migrations.

Regarding the latter, the tuna's counter-circulatory system enables rapid warming and conserves heat. This allows for extended cold water travel, as with the 5,000-mile-long trans-Pacific migration of Pacific bluefin. Warmth conservation also enables the southern bluefin's intense dives into frigid water.

Regulating their temperature has another benefit: it allows for a reliably warmer body temperature than the surrounding water, increasing the potential range of marine habitats. This helps explain why tuna live comfortably in the Arctic and tropical latitudes. Additionally, warm blood accelerates the tracking and identification of prey, as images flash across the tuna's eye more quickly when they swim faster.

A team from Trinity College Dublin collected data on wild bony fish and sharks using tiny waterproof biologging devices attached to hook-and-line captured fishes' fins. This catch-and-release process yielded a wealth of data on water temperatures various species encounter across diverse habitats and the speed and depths at which they swim. Data compared warm-blooded and cold-blooded species, and researchers found that warm-blooded fish swam, on average, 1.6 times faster than their cold-blooded counterparts.

It's worth noting that the tuna never stops swimming throughout its lifespan. This concerns its extreme musculature and elevated metabolism, which require a continuous flush of oxygen-rich water over the gills. Not all tuna fall into the warm-blooded category. While their blood vessels control the internal temperature of swimming muscles and organs, they do not keep the gills, which must handle large quantities of ocean water, heated. The only fish possessing full-body warm-bloodedness is the opah, which inhabits waters near Antarctica.

Interestingly, the Trinity College Dublin researchers found that tunas' ability to warm their bodies didn't translate into their inhabiting broader depth or temperature ranges. Climate scientists may be overemphasizing the warm-blooded species' resilience as ocean temperatures change due to global warming. With this in mind, and considering the vulnerable Pacific bluefin population is only four percent of where it was less than a century ago, scientists are considering measures such as catch limits that minimize overfishing and more robust enforcement of illegal fishing.

[joelfinley]

How Waves Form into Swells and Breaks

For surfers, wave types determine whether or not they can ride them. Successful surfers learn how waves form into swells and breaks.

While the breaking of waves may seem random, individuals can predict them by determining a combination of underwater topography and the energy that passes through water in a circular motion. Surface objects demonstrate the circularity effect of waves on surface objects, which (absent a surfboard) initially lurch forward and upward in the water but then fall down and backward to their original position as the wave passes through.

One way of looking at waves is through the lens of the forces that cause them—any disturbance to the surface of water results in waves that propagate in directions away from the force. When a pebble hits the surface of a still pond, waves take the form of ripples that spread in all directions as concentric circles.

When it comes to ocean waves, wind serves as a major driving force. Surface gravity waves refer to waves traveling in the same direction as air currents force because gravity ultimately acts as a restoring force. Storms, often thousands of miles away, generate gravity storms. They travel unimpeded, circularly under the surface, until they reach an insurmountable barrier such as a sandy shore or reef and break. Local winds and boat wakes can also generate smaller surface gravity waves. These quickly dissipate to a point where they are not noticeable.

On the other hand, tsunamis cause much larger surface gravity waves that break destructively along the coast. These reflect earthquakes or seismic shifts in underwater topography, as well as other types of forcing events, such as meteorite impacts, landslides, and volcanic eruptions under the water. Such events abruptly displace seawater of the same amplitude as the bottom shift, top to bottom, above the fracture, resulting in a tsunami.

The power, length, and duration of incoming waves define the swell. All swells start as small ripples on the ocean surface, which build up energy through sustained forces such as strong winds or underwater events. As they transform into waves, the ripples take form as sets or a series of waves that travel unimpeded until reaching the shoreline.

Swells extend underwater. When the leading edge, which drags along the seafloor, meets an obstruction, such as a reef (underwater rock formation) or sandy rise (culminating in a beach), the water slows, and the obstruction forces it upward to join the trailing edge of the swell at the surface. The wave rises as it travels until its height is such that gravity brings it back to the surface. It creates the break that surfers ride into shore.

The swell period, or the time required for a single wave crest to pass a fixed point before another wave rolls in, also comes into play. The swell period typically ranges from four to 22 seconds, with the length of the swell period determining the amount of water forced upward with each swell. Height is thus not the primary determining factor in wave strength; a three-foot wave with a 15-second swell period has significantly more force than a three-foot wave with a seven-second swell period.

For beginning surfers, calculating the time between swells helps them decide whether or not they can handle specific waves. Generally, a swell period of at least 12 seconds produces ridable waves or groundswells. The speed of the breaking wave is approximately three times the swell period, with a 12-second swell generating waves that travel up to 36 nautical miles.

[joelfinley]

Harpooning Bluefish Tuna in New England

Tuna is a sought-after fish that commands high prices on commercial markets. One way to catch large game fish in the open ocean is harpooning, which has been used for thousands of years. Harpooning is environmentally friendly and involves visually identifying fish of a specific size and species, thus avoiding the issue of bycatch, or catching many other marine species as in net fishing.

Harpooning is fundamentally different from rod and reel fishing, in which anglers use bait to attract fish. In harpooning, the boat actively pursues a targeted large fish, which must be 73 inches or longer, according to US law. This gives the fish several years to mature and reproduce, ensuring a steady supply of fish.

As described by a Massachusetts fisherman on the podcast Salt Life, there is a limited window of opportunity for local harpoon fishing, with bluefin tuna swimming near the surface in June and July. The tuna come up to the surface at this time because they are homeothermic, with a body temperature warmer than the water surrounding them. They feed at lower depths where the water is colder and digest near the surface in the top 10 feet of water.

Bluefin tuna harpooners must coordinate with the boat captain to locate schools of fish near the surface and position the vessel at speed so the target game fish is within throwing distance. Anglers must consider water refraction and sun angle, which can make the fish appear several feet from where it is.

As the Massachusetts harpooner describes it, the boat often rocks as it plows through the waves, and the fish swim “incredibly fast,” which means that accessibility is a major factor in targeting the fish. Ideally, the captain finds a line of tuna and slides in behind it before the fish become aware of the boat. “If they get a hint that you’re behind them, they’re gone before you can even think about throwing.”

The harpooner throws the harpoon from the front of the ship. The harpoon has a sharp-tipped dart, a pointed, heavy, machined brass or stainless steel piece designed to penetrate the fish. The dart connects to an aluminum rod known as the pike that the harpooner grasps. These two elements connect with the dart line, approximately 4 feet of three-strand 5/16-inch line. The harpooner attaches the dart line to a thicker, longer three-strand main line (the throwing line), typically 125 to 200 feet.

When the Massachusetts harpooner throws the harpoon and hits the tuna, an electric current similar to a Taser mobilizes it. The fish does not fight, which minimizes stress on the fish, allowing it to be taken onto the boat quickly and without a struggle. This is more humane and keeps the meat quality high.

Some commercial harpooning crews, as on the National Geographic show Wicked Tuna, use a spotter in a helicopter to identify lines of tuna in the ocean. The spotter conveys information to the crew in the boat via radio, alerting them where to head.

[joelfinley]

NHL Returning to Olympics in 2026

There hasn't been a best-on-best international ice hockey tournament since the World Cup of Hockey in 2016, but that will change in 2025 with the National Hockey League (NHL) 4 Nations Face-Off, a precursor to the league's return to the Olympics in 2026. Played from February 12 to 20 in Boston, Massachusetts, and Montreal, Quebec, the round-robin tournament will feature the United States, Canada, Sweden, and Finland. The following year, NHL players will be participating in the Olympics for the first time since the Sochi 2014 Games.

NHL Commissioner Gary Bettman said the 4 Nations Face-Off, held in place of the annual All-Star Game in the 2024-25 season, will be a one-off event. In an effort to provide fans with more best-on-best international hockey, the NHL will host the World Cup of Hockey in 2028 and has an agreement with the NHL Players Association (NHLPA) and the International Olympic Committee (IOC) to send players to the 2030 Olympics. The league intends to host the World Cup two years after every Winter Olympics.

Ice hockey has been part of the Winter Olympics since 1920, when Canada beat the United States 2-0 to win the gold medal in Antwerp, Belgium. Canada won six of the first seven Olympic gold medals, following which the Soviet Union enjoyed a dominant stretch, winning seven of nine gold medals. However, NHL players weren't permitted to play in the Olympics until the Nagano Games in 1998, meaning the Canadian and American teams were composed of amateur athletes - the US, with a roster of mostly college players, famously beat the Soviets in the "Miracle on Ice" game in 1980.

The Czech Republic won gold in the first of five consecutive Winter Olympics in which NHL players participated, beating Russia 1-0 in the final. Surprisingly, neither Canada nor the US medaled. However, the North American nations met in the gold medal game at Salt Lake City in 2002 and Vancouver in 2010, with Canada winning both games. Sweden beat Finland in the gold medal game in Torino in 2006, and Canada beat Sweden in the final in Sochi in 2014.

The NHL, NHLPA, and IOC couldn't agree on NHL player inclusion in the 2018 Games in PyeongChang largely due to travel costs and marketing rights. This appeared to be a one-off as all parties agreed to a deal for NHL participation in the Beijing 2022 Games in September 2021, but the NHL and NHLPA backed out a few months later after a COVID-19 outbreak that disrupted an already shortened schedule for the NHL.

The upcoming 4 Nations Face-Off will be the first time some of the NHL's best players, including Auston Matthews (USA) and Connor McDavid (Canada), get to represent their respective countries in best-on-best international hockey. Both Matthews and McDavid played in the World Cup in 2016 but were part of the U23 Team North America. McDavid has been an outspoken advocate for international hockey and for the NHL to return to the Olympics.

In June, the four teams in the 4 Nations Face-Off selected their first six players for the upcoming tournament. McDavid headlines Canada's group, which also includes Sidney Crosby and Nathan MacKinnon. Matthews is joined by Matthew Tkachuk, Jack Eichel, Quinn Hughes, Adam Fox, and Charlie McAvoy on Team USA.